Display bounding box around objects
Assuming you just want to display a bounding box around or instead of each object, you can do this with Draw types.

Drawing a bounding box instead of the object:

You could set Viewport shading to Bounding box to draw the bounds of each object:



A comparison between Solid and Bounding box:

 


To do this for one object only, you can set this in Properties > Object Display > Maximum draw type:





Drawing a bounding box around the object:

This can be done by enabling Bounds with the Maximum draw type still higher than Bounds:



This looks like this:



You could do this for many objects by:


Select the objects for which you want to enable Bounding box
Enable Bounds in Object > Display
Right click on the Bounds option and select Copy to selected: